Yamaha G100-112 series II - parametric EQ pops

[g-man]

I picked one up yesterday pretty cheap (it powered on but no signal...turns out the internal 4A fuse was blown). After replacing the fuse it powers up and works, at least it didn't blow any fuses during the ~30 minute test. I don't see any evidence of replaced components but it doesn't have any significant hum so I guess the electrolytic caps are holding up. Most of the pots need cleaning as they are a bit scratchy, but the middle pot in the parametric EQ section labeled Q makes a loud popping noise when adjusted. Loud enough that you wonder if it might damage the speaker. It only pops when being adjusted. Does anyone have an idea of what might cause this?

Thanks for any help.

g-man

[Jazz P Bass]

I would suggest cleaning the pot.
DeOxit by Caig works great.

[52 Bill]

Also check for any DC voltage on the pot from a leaky cap.

[g-man]

Yes, I was wondering if it might be stray voltage because it is much louder than the typical scratchy pot. So to check for it, just set my meter for DC and put the black probe on the chassis and the red probe to the pot wiper?

I will also clean it while cleaning the others when I get time to do it. The pcb has to be removed to get to all the pots. Thanks to you both.

[g-man]

Well spray cleaner seemed to do the trick. Dead quiet now. I guess it was just the loudest dirty pot I have encountered. Thanks.